AN ASSOCIATION OF PRIMARY ALDOSTERONISM AND ADRENALINE-SECRETING PHEOCHROMOCYTOMA

1. Two patients with adrenaline-only secreting phaeochromocytomas and primary aldosteronism were studied. 2. Urinary adrenaline levels were raised and plasma adrenaline was not suppressed normally following adm inistration of clonidine. Plasma aldosterone to plasma renin activity ratios were repeatedly elevated. 3. Both had large intra-adrenal phaeo chromocytomas visible on computerized tomography (CT) scanning. Surrou nding adrenal cortical tissue contained an adenoma in one and nodular hyperplasia in the other. 4. Following removal of the adrenal gland co ntaining the phaeochromocytoma, plasma and urinary adrenaline levels, and plasma aldosterone to plasma renin activity ratios returned to nor mal. 5. Adrenaline-only secreting phaeochromocytomas and primary aldos teronism have been rarely diagnosed even as separate entities, but rel iable screening tests are now available. 6. Simultaneous presence of t hese two conditions of hormone excess is probably a chance occurrence. Alternatively, there may be a genetic predisposition to endocrine dys plasia, or an interaction between the contiguous medullary and cortica l tissues, particularly after the normal architecture has been disturb ed by an enlarging phaeochromocytoma.